Cloyes Premium Race True Roller Double Roller Timing Chain Set 3 Keyway Adjustable 0.005 in Shorter Big Block Chevy HC720120 Rods have dowel pins for 001272011R Rods have dowel pins for precise fit and 12 point ARP cap screws compatible with hydraulic roller camshaftsMust be used with an MSD Ignition ControlSupplied with small diameter cap with HEI style terminals and race rotor (will accept 8441 Cap A Dapt)Nylon pads ensure smooth operation of the advance weightsAdvance weight pins are staked and tig welded to the plateMechanical advance assembly can be locked out for crank trigger systemsAdvance plate and weights are fine blanked from chrome moly steel and QPQ coated for friction reductionPolished steel shaft is QPQ coated and guided by a sealed ball bearingMaintenance free magnetic pickup and precision reluctor create stable trigger signals throughout the rpm rangeCNC machined billet aluminum housing and billet aluminum baseVacuum advance canister for improved economy (can be locked out)Easy to adjust mechanical advance with supplied springs and stop bushings┬ ¼Î“ÇáBillet housing is 5 8” smaller in diameter than stock Ford distributorsCARB E Cloyes has been manufacturing quality timing drives and components since the 1920's 3 Keyway Adjustable